Flexible tactile sensor and method for manufacturing the same

Abstract

Provided are a flexible tactile sensor and a method for manufacturing the same. The flexible tactile sensor includes a polymer layer, a first metal layer formed over the polymer layer and a first sensor layer formed over the first metal layer, the first sensor layer comprising a strain gauge configured to change its resistance according to a first strain and a metal wire connected to the strain gauge. The flexible tactile sensor also includes a first cover layer configured to protect the first sensor layer, a second metal layer formed under the polymer layer, a second sensor layer formed under the second metal layer. The second sensor layer includes a strain gauge configured to change its resistance according to a second strain and a metal wire connected to the strain gauge of the second metal layer and a second cover layer configured to protect the second sensor layer.

What is claimed is: 
     
       1. A flexible tactile sensor comprising:
 a polymer layer; 
 a first metal layer formed over the polymer layer, 
 a first sensor layer formed over the first metal layer, the first sensor layer comprising a strain gauge configured to change its resistance according to a first strain and a metal wire connected to the strain gauge; 
 a first cover layer configured to protect the first sensor layer; 
 a second metal layer formed under the polymer layer; 
 a second sensor layer formed under the second metal layer, the second sensor layer including a strain gauge configured to change its resistance according to a second strain and a metal wire connected to the strain gauge of the second metal layer; and 
 a second cover layer configured to protect the second sensor layer, 
 wherein the strain gauge of the first sensor layer includes a first pair of strain gauges including first and second strain gauges, wherein the metal wire of the first sensor layer includes a first pair of metal wires respectively connected to opposing ends of the first pair of strain gauges, 
 wherein the strain gauge of the second sensor layer includes a second pair of strain gauges including third and fourth strain gauges, wherein the metal wire of the second sensor layer includes a second pair of metal wires respectively connected to opposing ends of the second pair of strain gauges, 
 wherein a longitudinal axis of the first strain gauge and a longitudinal axis of the second strain gauge intersect with each other, 
 wherein a longitudinal axis of the third strain gauge and a longitudinal axis of the fourth strain gauge intersect with each other, and 
 wherein lengths of line widths and lengths of gaps between lines of the first and third strain gauges are different from lengths of line widths and gaps between lines of the second and fourth strain gauges. 
 
     
     
       2. The flexible tactile sensor of  claim 1 , wherein the longitudinal axis of each of the first to fourth strain gauges forms a predetermined angle with respect to a major surface of the polymer layer. 
     
     
       3. The flexible tactile sensor of  claim 2 , wherein each of the first and second pairs of strain gauges are spaced apart from each other and formed such that longitudinal axes thereof have a ‘≈’ shape. 
     
     
       4. The flexible tactile sensor of  claim 1 , wherein each of the first and second pairs of strain gauges have an ‘X’ shape. 
     
     
       5. The flexible tactile sensor of  claim 1 , wherein the longitudinal axes of the first and third strain gauges are perpendicular to each other and the longitudinal axes of the second and fourth strain gauges are perpendicular to each other, when viewed in a direction perpendicular to a major surface of the polymer layer. 
     
     
       6. A method for manufacturing a flexible tactile sensor, the method comprising:
 forming a first metal layer and a second metal layer on upper and lower surfaces of a polymer layer, respectively; 
 patterning a first pair of strain gauges including first and second strain gauges on an upper surface of the first metal layer and patterning a second pair of strain gauges including third and fourth strain gauges on a lower surface of the second metal layer; 
 patterning metal wires connected to the first pair of strain gauges and patterning metal wires connected to the second pair of strain gauges; and 
 forming a first cover layer protecting the first pair of strain gauges and the metal wires and forming a second cover layer protecting the second pair of strain gauges and the metal wires, 
 wherein the metal wires connected to the first pair of strain gauges include a first pair of metal wires respectively connected to opposing ends of the first pair of strain gauges, 
 wherein the metal wires connected to the second pair of strain gauges include a second pair of metal wires respectively connected to opposing ends of the second pair of strain gauges, 
 wherein a longitudinal axis of the first strain gauge and a longitudinal axis of the second strain gauge intersect with each other, 
 wherein a longitudinal axis of the third strain gauge and a longitudinal axis of the fourth strain gauge intersect with each other, and 
 wherein lengths of line widths and lengths of gaps between lines of the first and third strain gauges are different from lengths of line widths and gaps between lines of the second and fourth strain gauges. 
 
     
     
       7. A method for manufacturing a flexible tactile sensor, the method comprising:
 forming a first metal layer over a polymer layer; 
 patterning a first pair of strain gauges including first and second strain gauges over the first metal layer; 
 patterning metal wires connected to the first pair of strain gauges; 
 forming a first cover layer protecting the first pair of strain gauges and the metal wires; 
 forming a second metal layer under the polymer layer; 
 patterning a second pair of strain gauges including third and fourth strain gauges under the second metal layer; 
 patterning metal wires connected to the second pair of strain gauges; and 
 forming a second cover layer protecting the gauge pair of strain gauges and the metal wires, 
 wherein the metal wires connected to the first pair of strain gauges include a first pair of metal wires respectively connected to opposing ends of the first pair of strain gauges, 
 wherein the metal wires connected to the second pair of strain gauges include a second pair of metal wires respectively connected to opposing ends of the second pair of strain gauges, 
 wherein a longitudinal axis of the first strain gauge and a longitudinal axis of the second strain gauge intersect with each other, 
 wherein a longitudinal axis of the third strain gauge and a longitudinal axis of the fourth strain gauge intersect with each other, and 
 wherein lengths of line widths and lengths of gaps between lines of the first and third strain gauges are different from lengths of line widths and gaps between lines of the second and fourth strain gauges.